The purpose of this project is to study the metabolism of carbohydrates in explants of fetal rat liver hepatomas maintained in organ culture. We will study the effects of corticosteroid, glucagon, insulin, and cyclic nucleotides on the development of gluconeogenesis in these tissues, in order to evaluate if the known structural similarities between fetal liver and hepatoma are reflected in functional similarities as well. Techniques will be developed for growing tumors under organ culture conditions. Carbohydrate metabolisms of growing and static tissues will be compared.